|A New Echo Hiding Algorithm with High Robustness|
Echo hiding method boasts high watermark capacity but nothigh robustness. We propose a new echo hiding methodtaking advantage of both channels to replace the originalsingle echo hiding algorithm. Then, we propose a new echohiding algorithm combined with spread spectrum algorithmin Modulated Complex Lapped Transform domain. Theexperimental results show higher robustness compared withoriginal echo hiding method.
Keywords: Echo Hidin; Robustness; Channel; Capacity
|Pseudo-likelihood Inference for Gaussian Markov Random Fields|
Gaussian Markov random fields (GMRFs) are an important example of MRFs with many applications, particularly because GMRFs are known to provide effective approximations to any MRF. Despite their relative computational simplicity, inference in GMRFs using maximum likelihood (ML) is not always feasible. Therefore, this paper compares the inference quality using the pseudolikelihood, a well-known computational shortcut to full ML, and in addition the generalized lambda distribution is simulated to i...
Keywords: Gaussian Markov Random Fields; Pseudolikelihood; Robustness
|Data Fusion in Wind Tunnel Testing; Combined Pressure Paint and Model Deformation Measurements (Invited) - Bell, James H.|
As the benefit-to-cost ratio of advanced optical techniques for wind tunnel measurements such as Video Model Deformation (VMD), Pressure-Sensitive Paint (PSP), and others increases, these techniques are being used more and more often in large-scale production type facilities. Further benefits might be achieved if multiple optical techniques could be deployed in a wind tunnel test simultaneously. The present study discusses the problems and benefits of combining VMD and PSP systems...
Keywords: SUBSTRUCTURES; COMPUTATION; ROBUSTNESS (MATHEMATICS); COORDINATES; COMPENSATORS; ANALOGIES
|Analysis of Robustness Sliding Mode Control Method for Active Suspension System|
Taking vehicle transport into consideration, there are major systems that play important roles from the road to the body of the car to ensure the comfortability of the passengers. For that matter, the goal of car manufacturers is to develop the best suspension systems to guarantee this. In this article, active suspension system using a model of slide controller has been introduces with the purpose of advancing the comfort zone and accelerating vertically on passengers in the car...
Keywords: Robustness; Mode Control; Active Suspension System
|Treatment of outliers in samples of size three (Volume 70B) - Anscombe, F. J.|
Journal of Research of the National Bureau of Standards
Keywords: Statistics; outliers; residuals; estimation; robustness; least squares
|JHU Participation in 'Mission Scientist on the European Space Agency's Infrared Space Observatory' - Neufeld, David A|
The research funded work in support of the ISO GTO program ''Measurement of water vapor and oxygen abundances.'' Specific research included: (1) Theoretical modeling of the far-infrared water emission expected from shocked interstellar regions: (2) Theoretical modeling of the far-infrared water emission expected from circumstellar outflows from oxygen-rich evolved stars; (3) planning ISO observations, to test the predictions obtained through the modeling; and (4) Analyzing and interpreting far-i...
Keywords: ATTITUDE (INCLINATION); ROBUSTNESS (MATHEMATICS); STATISTICAL ANALYSIS; POLYNOMIALS; ALGORITHMS; EIGENVALUES; QUATERNIONS
|Dual-layer Digital Image Watermarking for Intellectual Property Right Protection|
Digital watermarking is a technique which is widelyused in various application areas such as copyright protection,copy control, broadcast monitoring etc. In this paper a noveldigital image watermarking technique is presented. To protectthe intellectual property rights, two different watermarks areinserted in host image. The first watermark is used to monitorthe any changes made in host image while second one is usedas proof of ownership...
Keywords: Digital Watermarking; Discrete Wavelet Transform; Fragile Watermark; LSB; Robustness
|Formation of the stable auroral arc that intensifies at substorm onset - Lyons, L. R.|
In a companion paper, we present observational evidence that the stable, growth-phase auroral arc that intensifies at substorm expansion phase onset often forms on magnetic field lines that map to within approximately 1 to 2 R(sub e) of synchronous. The equatorial plasma pressure is 1 to 10 nPa in this region, which can give a cross-tail current greater than 0.1 A/m. In this paper, we propose that the arc is formed by a perpendicular magnetospheric-current divergence that results from a strong d...
Keywords: POLYNOMIALS; ROBUSTNESS (MATHEMATICS); STABILITY; TRANSFER FUNCTIONS; COEFFICIENTS; LINEAR SYSTEMS
|ERIC ED387499: Analyzing Multivariate Repeated Measures Designs When Covariance Matrices Are Heterogeneous. - ERIC|
Methods for the analysis of within-subjects effects in multivariate groups by trials repeated measures designs are considered in the presence of heteroscedasticity of the group variance-covariance matrices and multivariate nonnormality. Under a doubly multivariate model approach to hypothesis testing, within-subjects main and interaction effect procedures are largely robust to the effects of heteroscedasticity when group sizes are equal, even when the data are nonnormal...
Keywords: ERIC Archive; Hypothesis Testing; Multivariate Analysis; Robustness (Statistics); Sample Size
|Optimization of Supersonic Transport Trajectories - Ardema, Mark D.|
This paper develops a near-optimal guidance law for generating minimum fuel, time, or cost fixed-range trajectories for supersonic transport aircraft. The approach uses a choice of new state variables along with singular perturbation techniques to time-scale decouple the dynamic equations into multiple equations of single order (second order for the fast dynamics). Application of the maximum principle to each of the decoupled equations, as opposed to application to the original coupled equations...
Keywords: DESIGN ANALYSIS; ROBUSTNESS (MATHEMATICS); STATISTICAL ANALYSIS; OPTIMIZATION; SAMPLING; SHEAR STRESS
|An MDOE Assessment of Nozzle Vanes for High Bypass Ratio Jet Noise Reduction - Henderson, Brenda|
The effect of airfoil-shaped vanes placed in the fan stream of a BPR 8 coannular nozzle model system on the resulting jet noise was investigated. The experiments used a Modern Design of Experiments approach to investigate the impact of a range of vane parameters on the noise reduction achieved at representative takeoff conditions. The experimental results showed that the installation of the vanes decreased low frequency noise radiation in the downstream peak-noise direction and increased high fr...
Keywords: MACHINE LEARNING; ROBUSTNESS (MATHEMATICS); GRADIENTS; TEMPORAL RESOLUTION; CONSTRAINTS; TRADEOFFS; DISTANCE
|Numerical studies of the conventional impact damper with discrete frequency optimization and uncertainty considerations - Ehsan Dehghan-Niri; S.M. Zahrai; A.F. Rod|
Abstract This paper presents the performance of a single horizontal conventional Impact Damper (ID) in both wide range frequency and resonance excitations. The effects of the coefficient of restitution, e, mass ratio, Î, and clearance, d, on the performance of ID are investigated. The optimal parameters are numerically found by discretely varying the clearance and excitation frequency. The performance of optimal ID is discussed, with respect to different parameters, in both resonance and off-re...
Keywords: Impact damper; Robustness; Resonance; Coefficient of restitution; Uncertainty
|Ground-Laboratory to In-Space Effective Atomic-Oxygen Fluence Determined for DC 93-500 Silicone - deGroh, Kim K.|
Surfaces on the leading edge of spacecraft in low Earth orbit (e.g., surface facing the velocity direction), such as on the International Space Station, are subject to atomic oxygen attack, and certain materials are susceptible to erosion. Therefore, ground-based laboratory testing of the atomic oxygen durability of spacecraft materials is necessary for durability assessment when flight data are not available...
Keywords: ROBUSTNESS (MATHEMATICS); RUNWAYS; PRECISION; PROTOTYPES; SPACING; AIRPORTS; ROUTES
|Ho:Tm:Er:LuAG and Two Wavelength Oscillation - Barnes, Norman P.|
Ho:Tm:Er:LuAG demonstrated simultaneous laser oscillation associated with two different transitions and different atoms. Two wavelength oscillation, or TWO, can be achieved in a single laser and single resonator. Moreover, the wavelength can be electronically controlled by varying the pump pulse length, Either the short wavelength, the Ho (5)1(sub 7) to (5)1(sub 8) transition at 2.1 microns, or the long wavelength, the Er (4)1(sub 11/2) to (4)1(sub 13/2) transition at 2.7 microns, or both wavele...
Keywords: EIGENVALUES; MATHEMATICAL MODELS; FORMULATIONS; DATA PROCESSING; ROBUSTNESS (MATHEMATICS); FREQUENCIES
|ACTIVE VIBRATION CONTROL OF SEISMICALLY EXCITED STRUCTURES BY ATMDS: STABILITY AND PERFORMANCE ROBUSTNESS PERSPECTIVE - ARASH MOHTAT; AGHIL YOUSEFI-KOMA; EHSAN DEHGHAN-NIRI|
This paper demonstrates the trade-oÂ® between nominal performance and robustness in intelligent and conventional structural vibration control schemes; and, proposes a systematic treatment of stability robustness and performance robustness against uncertainty due to structural damage. The adopted control strategies include an intelligent genetic fuzzy logic controller (GFLC) and reduced-order observer-based (ROOB) controllers based on pole-placement and linear quadratic regulator (LQR) conventi...
Keywords: Stability robustness; performance robustness; uncertainty due to damage; genetic fuzzy logic controller (GFLC); pole-placement; LQR; bridge; ATMD system
|Impact of a process improvement program in a production software environment: Are we any better - Heller, Gerard H.|
For the past 15 years, Computer Sciences Corporation (CSC) has participated in a process improvement program as a member of the Software Engineering Laboratory (SEL), which is sponsored by GSFC. The benefits CSC has derived from involvement in this program are analyzed. In the environment studied, it shows that improvements were indeed achieved, as evidenced by a decrease in error rates and costs over a period in which both the size and the complexity of the developed systems increased substanti...
Keywords: MONTE CARLO METHOD; LOCI; PROBABILITY THEORY; ROBUSTNESS (MATHEMATICS); STABILITY; STOCHASTIC PROCESSES; ACTUATORS; BINARY DATA; ESTIMATES; HISTOGRAMS
|NASA/DoD Aerospace Knowledge Diffusion Research Project. Paper 29: The US government technical report and the transfer of federally funded aerospace R and D - Pinelli, Thomas E.|
This article discusses the U.S. government technical report and the transfer of federally funded aerospace research and development in a conceptual framework of the federal government as a producer of scientific and technical information. The article summarizes current literature and research and discusses U.S. government technical report use and the importance of using data obtained from the NASA/DoD Aerospace Knowledge Diffusion Research Project...
Keywords: CONTROL STABILITY; CONTROLLERS; COST ANALYSIS; MATHEMATICAL MODELS; ROBUSTNESS (MATHEMATICS); APPROXIMATION; PERTURBATION THEORY
|Computation of Passive Robustness Bound for Assembly/Disassembly Processes|
Works presented in this paper deal with the robustness ofmanufacturing job‐shops with time constraints. A computingalgorithm of a lower bound of the maximal time disturbancesallowed in a given point is provided. To demonstrate theeffectiveness and accuracy of this algorithm, two industrialexamples are depicted. The possession of this bound allowschecking the death of marks without the generation of toomany false alarms...
Keywords: P-time Petri Net; Manufacturing System; Passive Robustness; Sojourn Time Constraints; Time Disturbance
|EFFECTIVENESS ROBUSTNESS COMPROMISE FOR OPTIMUM DESIGN OF MTMD SYSTEMS THROUGH MULTI OBJECTIVE GA OPTIMIZATION - Ehsan Dehghan-Niri; A. Mohtat; S. M. Zahrai|
Multiple tuned mass dampers (MTMD) consisting of many TMDs with equally distributed natural frequencies are considered for attenuating effectively the response of uncertain structures to harmonic force excitation. Considering the uncertainty in the natural frequency of the structural mode being controlled, the concept of nominal effectiveness is not the only aspect that characterizes performance; the robust effectiveness must also be addressed...
Keywords: multiple tuned mass damper (MTMD); optimal design methodology; effectiveness; robustness; multi-objective GA; Pareto-optimal solutions
|ERIC ED317601: Feel No Guilt! Your Statistics Are Probably Robust. - ERIC|
This paper reports an attempt to identify appropriate and robust location estimators for situations that tend to occur among various types of empirical data. Emphasizing robustness across broad unidentifiable ranges of contamination, an attempt was made to replicate, on a somewhat smaller scale, the definitive Princeton Robustness Study of 1972 to determine how closely results produced in a laboratory environment represent the multiple contaminations encountered among real world data...
Keywords: ERIC Archive; Educational Research; Equations (Mathematics); Estimation (Mathematics); Mathematical Models; Psychometrics; Robustness (Statistics); Statistical Analysis
|Predicted and measured strain responses of isotropic panels to base excitation - Lyle, Karen H.|
The accuracy of classical linear theory for predicting acceleration and strain for cantilevered and Clamped-Free-Clamped-Free (C-F-C-F) panels excited through the base is studied. Aluminum, steel and titanium plates of various dimensions and thicknessess were vibration tested, using a broadband random signal applied through a shaker mounting fixture. The strains were measured at 9 locations on the cantilevered panels and at 5 locations on the C-F-C-F panels...
Keywords: ADAPTIVE CONTROL; PHASES; EXCITATION; LINEAR SYSTEMS; ROBUSTNESS (MATHEMATICS); ALGORITHMS; CONVERGENCE; COVARIANCE; LEAST SQUARES METHOD; MATRICES (MATHEMATICS)
|Funtools: Fits Users Need Tools for Quick, Quantitative Analysis - Mandel, Eri|
The Funtools project arose out of conversations with astronomers about the decline in their software development efforts over the past decade. A stated reason for this decline is that it takes too much effort to master one of the existing FITS libraries simply in order to write a few analysis programs. This problem is exacerbated by the fact that astronomers typically develop new programs only occasionally, and the long interval between coding efforts often necessitates re-learning the FITS inte...
Keywords: UPWIND SCHEMES (MATHEMATICS); UNSTRUCTURED GRIDS (MATHEMATICS); FACTORIZATION; ROBUSTNESS (MATHEMATICS); COMPUTATIONAL FLUID DYNAMICS; TRIANGLES
|Higher Harmonic Control for Tiltrotor Vibration Reduction - Nixon, Mark W.|
The results of a joint NASA/Army/Bell Helicopter Textron wind-tunnel test to assess the potential of higher harmonic control (HHC) for reducing vibrations in tiltrotor aircraft operating in the airplane mode of flight, and to evaluate the effectiveness of a Bell-developed HHC algorithm called MAVSS (Multipoint Adaptive Vibration Suppression System) are presented. The test was conducted in the Langley Transonic Dynamics Tunnel using an unpowered 1/5- scale semispan aeroelastic model of the V-22 w...
Keywords: ATTITUDE CONTROL; CONTROL THEORY; SIMULATION; SMALL SATELLITE TECHNOLOGY; NONLINEAR PROGRAMMING; ROBUSTNESS (MATHEMATICS); SPACECRAFT CONTROL
|Progress of Multicolor Single Detector to Detector Array Development for Remote Sensing - Abedin, M. Nurul|
Knowledge of the spatial and temporal distribution of atmospheric species such as CO2, O3, H2O, and CH4 is important for understanding the chemistry and physical cycles involving Earth s atmosphere. Although several remote sensing techniques are suitable for such measurements they are considered high cost techniques involving complicated instrumentation. Therefore, simultaneous measurement of atmospheric species using a single remote sensing instrument is significant for minimizing cost, size an...
Keywords: CERAMICS; THIN FILMS; THERMOCOUPLES; HIGH TEMPERATURE ENVIRONMENTS; ROBUSTNESS (MATHEMATICS); STABILITY; NOBLE METALS
|ERIC ED388691: A Comparison of the Type I Error and Power of Selected MANOVA Simultaneous Test Procedures. - ERIC|
A Monte Carlo study was conducted using the Statistical Analysis System IML computer program to compare the multivariate analysis of variance (MANOVA) simultaneous test procedures of Roy's Greatest Root, the Pillai-Bartlett trace, the Hotelling-Lawley trace, and Wilks' lambda, in terms of power and Type I error under various conditions, including violations of MANOVA assumptions. The Type I error rates of moderately-restricted contrasts in simultaneous test procedures following a significant omn...
Keywords: ERIC Archive; Analysis of Variance; Comparative Analysis; Monte Carlo Methods; Multivariate Analysis; Power (Statistics); Robustness (Statistics)
|A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate - NON|
A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate is disclosed. The process may be used to prepare both rigid and flexible cables and circuit boards. A substrate is provided and a polymeric solution comprising a self-bonding, soluble polymer and a solvent is applied to the substrate. Next, the polymer solution is dried to form a polymer coated substrate...
Keywords: SYSTEMS STABILITY; RICCATI EQUATION; ENERGY DISSIPATION; LINEAR SYSTEMS; ROBUSTNESS (MATHEMATICS); STABILIZATION; CONTROLLERS; INEQUALITIES
|Keeping a Spacecraft on the Sun-Earth Line - Roithmayr, Carlos M.|
Measurements of Earth's atmosphere as it occults sunlight can be obtained advantageously from a spacecraft placed in the proximity of the Sun-Earth Lagrange point L2. Maintaining the condition of continuous solar occultation by all parts of the atmospheric disk requires that the displacement of the spacecraft perpendicular to the Sun-Earth line remains less than 200 km. However, the gravitational force exerted by the Earth's moon must be negated by propulsion in order to meet this rather tight c...
Keywords: ALGORITHMS; MONKEYS; EVOKED RESPONSE (PSYCHOPHYSIOLOGY); BIOELECTRIC POTENTIAL; MAGNETIC FIELDS; ELECTRIC FIELDS; VARIABILITY; SIMULATION; ROBUSTNESS (MATHEMATICS); NEURONS
|Thermal Insulation Performance of Flexible Piping for Use in HTS Power Cables - Fesmire, James E.|
High-temperature superconducting (HTS) cables that typically operate at temperatures below 80 K are being developed for power transmission. The practical application of HTS power cables will require the use of flexible piping to contain the cable and the liquid nitrogen coolant. A study of thermal performance of multilayer insulation (MLI) was conducted in geometries representing both rigid and flexible piping...
Keywords: ACTUATORS; CONTROLLERS; DEGRADATION; FAILURE ANALYSIS; FLEXIBLE BODIES; CONTROL SYSTEMS DESIGN; ROBUSTNESS (MATHEMATICS)
|Study of auroral dynamics with combined spacecraft and incoherent scatter radar data - Thayer, Jeffrey P.|
The objectives of this project were to study the coupling between the ionosphere and the magnetosphere, and to understand how this coupling was affected by changes in the solar wind. The data used consisted of satellite measurements coordinated with Sondrestrom incoherent scatter radar observations. We focused our efforts on the study of temporal and spatial changes in the dayside auroral precipitation and electric field.
Keywords: INVERSE KINEMATICS; MANIPULATORS; ROBUSTNESS (MATHEMATICS); WEIGHTING FUNCTIONS; APPROXIMATION; MATRICES (MATHEMATICS); SINGULARITY (MATHEMATICS); TELEOPERATORS
|Generalized frame work for robust design of tuned mass damper systems - A. Mohtat; Ehsan Dehghan-Niri|
The primary purpose of this contribution is to develop a novel framework for generalized robust design of tuned mass damper(TMD)systems as passive vibration controllers for uncertain structures.This versatile strategy is intended to be free of any restriction on the structure TMD system configuration,the performance criterion,and the number of uncertain parameters.The main idea pursued is to adopt methods and concepts from the robust control literature,including:(1)the linear fractional transfor...
Keywords: multiple tuned mass damper (MTMD); Genetic Algorithm; effectiveness; robustness; multi-objective GA; Pareto-optimal solutions
|Digital Tipping Point: computer science student Josh Abraham 02 - Christian Einfeldt|
This is one of many short video segments which will be added to the Digital Tipping Point (DTP) archive. In this segment, Josh Abraham recounts his memories of preparing web pages using Linux (GNU/Linux) on a 486 as opposed to using Notepad under Microsoft Windows. He says that he was able to keep 12 console terminal windows open under Linux, which made his work much faster than under Microsoft Windows...
Keywords: Josh Abraham; Abraham, Josh; Coolness Of Open Source Software; Linux, Robustness Of
|High Capacity Robust Medical Image Data Hiding using CDCS with Integrity Checking|
While transferring electronic patient report (EPR)data along with corresponding medical images over network,confidentiality must be assured. This can be achieved byembedding EPR data in corresponding medical image itself.However, as the size of EPR increases, security androbustness of the embedded information becomes major issueto monitor. Also checking the integrity of this embedded datamust be needed in order to assure that retrieved EPR data isoriginal and not manipulated by different types o...
Keywords: Medical image; EPR; Data hiding; Stego image; ROI; Robustness; Security; Integrity Check
|Hypersonic Boundary Layer Stability over a Flared Cone in a Quiet Tunnel - Lachowicz, Jason T.|
Hypersonic boundary layer measurements were conducted over a flared cone in a quiet wind tunnel. The flared cone was tested at a freestream unit Reynolds number of 2.82x106/ft in a Mach 6 flow. This Reynolds number provided laminar-to-transitional flow over the model in a low-disturbance environment. Point measurements with a single hot wire using a novel constant voltage anemometry system were used to measure the boundary layer disturbances...
Keywords: SYSTEMS ENGINEERING; ACTUATORS; CONTROL SYSTEMS DESIGN; FLEXIBLE BODIES; DISSIPATION; FEEDBACK CONTROL; NONLINEAR PROGRAMMING; ROBUSTNESS (MATHEMATICS)
|Analytical Prediction of Damage Growth in Notched Composite Panels Loaded in Axial Compression - Ambur, Damodar R.|
A progressive failure analysis method based on shell elements is developed for the computation of damage initiation and growth in stiffened thick-skin stitched graphite-epoxy panels loaded in axial compression. The analysis method involves a step-by-step simulation of material degradation based on ply-level failure mechanisms. High computational efficiency is derived from the use of superposed layers of shell elements to model each ply orientation in the laminate...
Keywords: PARAMETERIZATION; MATHEMATICAL MODELS; SET THEORY; UNCERTAIN SYSTEMS; FEASIBILITY ANALYSIS; SIMULATION; EIGENVALUES; ROBUSTNESS (MATHEMATICS); LINEAR TRANSFORMATIONS
|Dan Stowell research video, QMROD 2008: Robustness of vocal timbre features in live performance contexts - Dan Stowell|
A short (3-minute) video lecture on my research into "Robustness of vocal timbre features in live performance contexts"
Keywords: research; audio; digital; music; voice; singing; speech; beatboxing; robustness; timbre; features; signal processing
|A method for tailoring the information content of a software process model - Perkins, Sharon|
The framework is defined for a general method for selecting a necessary and sufficient subset of a general software life cycle's information products, to support new software development process. Procedures for characterizing problem domains in general and mapping to a tailored set of life cycle processes and products is presented. An overview of the method is shown using the following steps: (1) During the problem concept definition phase, perform standardized interviews and dialogs between dev...
Keywords: ARTIFICIAL INTELLIGENCE; CONTROL SYSTEMS DESIGN; FAULT TOLERANCE; NEURAL NETS; RELIABILITY ENGINEERING; ROBUSTNESS (MATHEMATICS); MAINTAINABILITY; REDUNDANCY
|Effectiveness-robustness objectives in MTMD system design: An evolutionary optimal design methodology - Ehsan Dehghan-Niri; S. M. Zahrai;A. Mohtat|
The main contribution pursued in this investigation is to propose a generic optimal methodology for designing multiple tuned mass damper (MTMD) systems to efficiently suppress the response of uncertain structures to harmonic excitations. This methodology comprises quantitative indexing of MTMD effectiveness and robustness as performance criteria, implementing a two objective optimization and presenting solutions as optimal set of non-dominated designs...
Keywords: multiple tuned mass damper (MTMD); optimal design methodology; effectiveness; robustness; multi-objective GA; Pareto-optimal solutions
|18. A Novel Technique.full|
Proposed paper present a new robust watermarking technique for copyright protection based on Discrete Wavelet Transform and Singular Value Decomposition. The Low frequency sub band of the wavelet decomposed cover image is modified by modifying its singular values. A secret key is generated from the original watermark with the help of visual cryptography to claim the ownership of the image. The ownership of the image can be claimed by superimposing this secret key on the extracted watermark from ...
Keywords: Image Watermarking; Visual Cryptography; Singular Value Decomposition; Discrete WaveletTransform; Robustness; Steganography
|Calibration of the Langley 8-Foot High Temperature Tunnel for Hypersonic Airbreathing Propulsion Testing - Huebner, Lawrence D.|
The NASA Langley 8-Foot High Temperature Tunnel has recently been modified to produce a unique testing capability for hypersonic airbreathing propulsion systems. Prior to these modifications, the facility was used primarily for aerothermal loads and structural verification testing at true flight total enthalpy conditions for Mach numbers between 6 and 7. One of the recent modifications was an oxygen replenishment system which allows operating airbreathing propulsion systems to be tested at true ...
Keywords: MULTIVARIABLE CONTROL; DESIGN ANALYSIS; FEEDBACK; SUBSTRUCTURES; STIFFNESS MATRIX; MODELS; ROBUSTNESS (MATHEMATICS)
|Software Engineering Laboratory Series: Proceedings of the Twenty-Second Annual Software Engineering Workshop - NON|
The Software Engineering Laboratory (SEL) is an organization sponsored by NASA/GSFC and created to investigate the effectiveness of software engineering technologies when applied to the development of application software. The activities, findings, and recommendations of the SEL are recorded in the Software Engineering Laboratory Series, a continuing series of reports that includes this document.
Keywords: COMPUTER PROGRAMS; ICE FORMATION; VARIABILITY; DATA BASES; ROBUSTNESS (MATHEMATICS); WEATHER; SPACING; SHAPES
|On The Computational Capabilities of Physical Systems - Wolpert, David H|
In the first of this pair of papers, it was proven that there cannot be a physical computer to which one can properly pose any and all computational tasks concerning the physical universe. It was then further proven that no physical computer C can correctly carry out all computational tasks that can be posed to C. As a particular example, this result means that no physical computer that can, for any physical system external to that computer, take the specification of that external system's state...
Keywords: AIRFOILS; SHAPE OPTIMIZATION; STATISTICAL ANALYSIS; COMPUTATIONAL FLUID DYNAMICS; MACH NUMBER; COMPUTATIONAL GRIDS; ROBUSTNESS (MATHEMATICS); AERODYNAMIC DRAG
|Fractal Characterization of Multitemporal Remote Sensing Data - Quattrochi, Dale A.|
Scale is an ''innate'' concept in geographic information systems. It is recognized as something that is intrinsic to the capture, storage, manipulation, analysis, modeling, and output of space and time data within a GIS purview, yet the relative meaning and ramifications of scaling spatial and temporal data from this perspective remain enigmatic. As GISs become more sophisticated as a product of more robust software and more powerful computer systems, there is an urgent need to examine the issue...
Keywords: ROBUSTNESS (MATHEMATICS); COMPONENT RELIABILITY; STRUCTURAL ANALYSIS; ALGORITHMS; TWO DIMENSIONAL MODELS; COMPUTERIZED SIMULATION; FORMULATIONS; FREQUENCIES; DAMPING; DYNAMIC MODELS; DYNAMIC CONTROL
|ERIC ED359231: Multivariate Test Statistics and Their Approximations: Some Problems. - ERIC|
This Monte Carlo study examines whether, given various numbers of variables, treatments, and sample sizes, in a one-way multivariate analysis of variance, Type I error rates of the test approximations provided by the BMDP program, the Statistical Analysis System (SAS), and the Statistical Package for the Social Sciences (SPSS) for Roy's largest root, Hotelling's trace, Wilks' likelihood ratio, and P...
Keywords: ERIC Archive; Analysis of Variance; Computer Simulation; Estimation (Mathematics); Monte Carlo Methods; Multivariate Analysis; Probability; Robustness (Statistics); Sample Size
|ERIC ED365730: The Effects of Single and Compound Violations of Data Set Assumptions when Using the Oneway, Fixed Effects Analysis of Variance and the One Concomitant Analysis of Covariance Statistical Models. - ERIC|
This study integrates into one comprehensive Monte Carlo simulation a vast array of previously defined and substantively interrelated research studies of the robustness of analysis of variance (ANOVA) and analysis of covariance (ANCOVA) statistical procedures. Three sets of balanced ANOVA and ANCOVA designs (group sizes of 15, 30, and 45) and one set of unbalanced ANOVA and ANCOVA designs (groups of 15, 30, and 45) were simulated...
Keywords: ERIC Archive; Analysis of Covariance; Analysis of Variance; Computer Simulation; Models; Monte Carlo Methods; Robustness (Statistics); Sample Size; Sampling
|Automated Inspection of the RSRM Case O-Ring Seal Surface - ODell, Keith P|
An automated inspection system has been developed to inspect the o-ring sealing surfaces on the Space Shuttle reusable solid rocket motor (RSRM) case segment joints. A laser digitizing system is used to create a three dimensional map of the o-ring sealing surfaces. This data is analyzed for any irregularities, which are noted for further inspection and disposition. This paper describes both the hardware and the software used to gather data as well as the methods developed to analyze the data...
Keywords: COMPUTERIZED SIMULATION; PARACHUTES; TRAJECTORIES; MONTE CARLO METHOD; AEROMANEUVERING; MARS LANDING; DESIGN ANALYSIS; ROBUSTNESS (MATHEMATICS); RANDOM VARIABLES; SUPERSONICS; DEPLOYMENT
|ERIC ED371019: Robustness of Unidimensional IRT Calibration in the Presence of Essential Dimensionality. - ERIC|
The first purpose of this study was to investigate the stability of two essential dimensionality measures across 10 random samples within a particular assessment item (AT1) selection. Other purposes were to investigate the discrepancy of the essential unidimensionality estimates for a test across different AT1 selections and sample sizes and to investigate the validity of replacing the item response theory (IRT) unidimensionality assumption with the essential unidimensionality assumption using t...
Keywords: ERIC Archive; Correlation; Educational Assessment; Estimation (Mathematics); Item Response Theory; Robustness (Statistics); Sample Size; Selection; Test Format; Test Items
|ERIC ED325492: The Robustness of Regression and Substitution by Mean Methods in Handling Missing Values. - ERIC|
There are times in survey research when missing values need to be estimated. The robustness of four variations of regression and substitution by mean methods was examined using a 3x3x4 factorial design. The regression variations included in the study were: (1) regression using a single best predictor; (2) two best predictors; (3) all available preditors having observed values; and (4) all available predictors with adjustment of estimate for predictors having missing values...
Keywords: ERIC Archive; Comparative Analysis; Computer Simulation; Estimation (Mathematics); Predictor Variables; Regression (Statistics); Research Problems; Robustness (Statistics); Sample Size; Surveys
|Effects of Mean Flow Profiles on Instability of a Low-Density Gas Jet Injected into a High-Density Gas - Vedantam, Nanda Kishor|
The objective of this study was to investigate the effects of the mean flow profiles on the instability characteristics in the near-injector region of low-density gas jets injected into high-density ambient gas mediums. To achieve this, a linear temporal stability analysis and a spatio-temporal stability analysis of a low-density round gas jet injected vertically upwards into a high-density ambient gas were performed by assuming three different sets of mean velocity and density profiles...
Keywords: ROBUSTNESS (MATHEMATICS); COMPUTATIONAL FLUID DYNAMICS; UNCERTAIN SYSTEMS; SENSITIVITY; DERIVATION; METHOD OF MOMENTS; RANDOM VARIABLES; APPROXIMATION; MONTE CARLO METHOD
|ERIC ED319794: Measurement Model Specification Error in LISREL Structural Equation Models. - ERIC|
This LISREL study examines the robustness of the maximum likelihood estimates under varying degrees of measurement model misspecification. A true model containing five latent variables (two endogenous and three exogenous) and two indicator variables per latent variable was used. Measurement model misspecification considered included errors of omission, errors of inclusion, and simultaneous errors of omission and inclusion...
Keywords: ERIC Archive; Computer Software; Error of Measurement; Item Response Theory; Mathematical Models; Maximum Likelihood Statistics; Robustness (Statistics)
|ERIC ED363648: Orthogonal Regression and Equivariance. - ERIC|
Ordinary least-squares regression treats the variables asymmetrically, designating a dependent variable and one or more independent variables. When it is not obvious how to make this distinction, a researcher may prefer to use orthogonal regression, which treats the variables symmetrically. However, the usual procedure for orthogonal regression is not equivariant. A simple modification is proposed to overcome this serious defect...
Keywords: ERIC Archive; Equations (Mathematics); Estimation (Mathematics); Least Squares Statistics; Mathematical Models; Regression (Statistics); Research Methodology; Robustness (Statistics)